CVE-2026-29905: Kirby CMS through 5.1.4 allows an authenticated user with 'Editor' permissions to cause a persistent Denial of

Q: How do I fix CVE-2026-29905?

kirby: upgrade to newer than 5.1.4. Exact commands for each OS are on this page.

Q: Is CVE-2026-29905 being exploited?

CVE-2026-29905 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-29905 affect?

CVE-2026-29905 affects kirby. Severity is medium (CVSS 6.5). Kirby CMS through 5.1.4 allows an authenticated user with 'Editor' permissions to cause a persistent Denial of Service (DoS) via a malformed image upload. The application fails to properly validate the return value of the PHP getimagesize()

Q: How urgent is CVE-2026-29905?

Priority 38/100. Public exploit reference

Routine

MEDIUM 6.5UPGRADE

CVE-2026-29905 is a medium-severity flaw (CVSS 6.5) affecting kirby. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Kirby CMS through 5.1.4 allows an authenticated user with 'Editor' permissions to cause a persistent Denial of Service (DoS) via a malformed image upload. The application fails to properly validate the return value of the PHP getimagesize() function. When the system attempts to process this file for metadata or thumbnail generation, it triggers a fatal TypeError.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-20, CWE-252
Published	2026-03-26
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: getkirby

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-26 17:16 UTCPublished CVE record published
2026-06-17 10:29 UTCUpdated Record last modified

getkirby kirby UPGRADE

Affected: <= 5.1.4

Fixed in: newer than 5.1.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy kirby || rpm -q kirby || kirby --version

2. UPGRADE to newer than 5.1.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade kirby

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade kirby

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-29905?

kirby: upgrade to newer than 5.1.4. Exact commands for each OS are on this page.

Is CVE-2026-29905 being exploited?

CVE-2026-29905 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-29905 affect?

CVE-2026-29905 affects kirby. Severity is medium (CVSS 6.5). Kirby CMS through 5.1.4 allows an authenticated user with 'Editor' permissions to cause a persistent Denial of Service (DoS) via a malformed image upload. The application fails to properly validate the return value of the PHP getimagesize()

How urgent is CVE-2026-29905?

Priority 38/100. Public exploit reference

Software pages

PHP vulnerabilities

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References

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